We use SoVolumeMask to associate (mark) each vertebra with the corresponding mask (L1, L2 and L3.lda). Then, each selected vertebra is rendered by using different mechanisms such as volume rendering or isosurface. SoVolumeDataDrawStyle is used to combine these two types of rendering. A transfer function is associated for each masked vertebra. That is the reason why each vertebra are rendered in different colors.

Limitation: This demo is not available on 32 bit Windows architectures as it requires more than 4 GB of memory to be run.